Difficulty

It's very hard for three stars. It's impossible to three stars if you didn't destroy crystals enough.

Strategy

Launch Lazer Bird below the first planet on the left, and redirect him towards the top end of the wooden plank holding the TNT box. The gravity should pull everything towards the center planet, destroying all the pigs there. Then launch Terence above the planets on a long curve. The gravity should pull the bird back towards the center, skimming the bottom right crystals and bounce of the square trampoline on the left. This will send him towards the last group of pigs, destroying them.